[Intel-gfx] [PATCH v2 01/22] drm/i915/dp: Factor out helpers to compute the link limits

Imre Deak imre.deak at intel.com
Mon Sep 4 10:25:12 UTC 2023


On Mon, Sep 04, 2023 at 06:19:04AM +0300, Ville Syrjälä wrote:
> On Thu, Aug 24, 2023 at 11:04:56AM +0300, Imre Deak wrote:
> > Factor out helpers that DP / DP_MST encoders can use to compute the link
> > rate/lane count and bpp limits. A follow-up patch will call these to
> > recalculate the limits if DSC compression is required.
> > 
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_dp.c     | 61 +++++++++++++--------
> >  drivers/gpu/drm/i915/display/intel_dp_mst.c | 52 ++++++++++--------
> >  2 files changed, 68 insertions(+), 45 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 7067ee3a4bd36..53697f361f950 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -2187,29 +2187,25 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> >  	return 0;
> >  }
> >  
> > -static int
> > -intel_dp_compute_link_config(struct intel_encoder *encoder,
> > -			     struct intel_crtc_state *pipe_config,
> > -			     struct drm_connector_state *conn_state,
> > -			     bool respect_downstream_limits)
> > +static void
> > +intel_dp_compute_config_limits(struct intel_dp *intel_dp,
> > +			       struct intel_crtc_state *crtc_state,
> > +			       bool respect_downstream_limits,
> > +			       struct link_config_limits *limits)
> >  {
> > -	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> > -	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
> > +	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> >  	const struct drm_display_mode *adjusted_mode =
> > -		&pipe_config->hw.adjusted_mode;
> > -	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> > -	struct link_config_limits limits;
> > -	bool joiner_needs_dsc = false;
> > -	int ret;
> > +		&crtc_state->hw.adjusted_mode;
> >  
> > -	limits.min_rate = intel_dp_common_rate(intel_dp, 0);
> > -	limits.max_rate = intel_dp_max_link_rate(intel_dp);
> > +	limits->min_rate = intel_dp_common_rate(intel_dp, 0);
> > +	limits->max_rate = intel_dp_max_link_rate(intel_dp);
> >  
> > -	limits.min_lane_count = 1;
> > -	limits.max_lane_count = intel_dp_max_lane_count(intel_dp);
> > +	limits->min_lane_count = 1;
> > +	limits->max_lane_count = intel_dp_max_lane_count(intel_dp);
> >  
> > -	limits.min_bpp = intel_dp_min_bpp(pipe_config->output_format);
> > -	limits.max_bpp = intel_dp_max_bpp(intel_dp, pipe_config, respect_downstream_limits);
> > +	limits->min_bpp = intel_dp_min_bpp(crtc_state->output_format);
> > +	limits->max_bpp = intel_dp_max_bpp(intel_dp, crtc_state,
> > +					   respect_downstream_limits);
> >  
> >  	if (intel_dp->use_max_params) {
> >  		/*
> > @@ -2220,16 +2216,35 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> >  		 * configuration, and typically on older panels these
> >  		 * values correspond to the native resolution of the panel.
> >  		 */
> > -		limits.min_lane_count = limits.max_lane_count;
> > -		limits.min_rate = limits.max_rate;
> > +		limits->min_lane_count = limits->max_lane_count;
> > +		limits->min_rate = limits->max_rate;
> >  	}
> >  
> > -	intel_dp_adjust_compliance_config(intel_dp, pipe_config, &limits);
> > +	intel_dp_adjust_compliance_config(intel_dp, crtc_state, limits);
> 
> Annoying little bugger that mutates the crtc_state. Would be nice
> to relocate that small part somewhere else so that we could constify
> things more...

Yes, it could set dither_force_disable later separately.

> Anyways
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> >  
> >  	drm_dbg_kms(&i915->drm, "DP link computation with max lane count %i "
> >  		    "max rate %d max bpp %d pixel clock %iKHz\n",
> > -		    limits.max_lane_count, limits.max_rate,
> > -		    limits.max_bpp, adjusted_mode->crtc_clock);
> > +		    limits->max_lane_count, limits->max_rate,
> > +		    limits->max_bpp, adjusted_mode->crtc_clock);
> > +}
> > +
> > +static int
> > +intel_dp_compute_link_config(struct intel_encoder *encoder,
> > +			     struct intel_crtc_state *pipe_config,
> > +			     struct drm_connector_state *conn_state,
> > +			     bool respect_downstream_limits)
> > +{
> > +	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> > +	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
> > +	const struct drm_display_mode *adjusted_mode =
> > +		&pipe_config->hw.adjusted_mode;
> > +	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> > +	struct link_config_limits limits;
> > +	bool joiner_needs_dsc = false;
> > +	int ret;
> > +
> > +	intel_dp_compute_config_limits(intel_dp, pipe_config,
> > +				       respect_downstream_limits, &limits);
> >  
> >  	if (intel_dp_need_bigjoiner(intel_dp, adjusted_mode->crtc_hdisplay,
> >  				    adjusted_mode->crtc_clock))
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > index 3eb085fbc7c82..218c2dfd57adc 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > @@ -306,6 +306,35 @@ static bool intel_dp_mst_has_audio(const struct drm_connector_state *conn_state)
> >  		return intel_conn_state->force_audio == HDMI_AUDIO_ON;
> >  }
> >  
> > +static void
> > +intel_dp_mst_compute_config_limits(struct intel_dp *intel_dp,
> > +				   struct intel_crtc_state *crtc_state,
> > +				   struct link_config_limits *limits)
> > +{
> > +	/*
> > +	 * for MST we always configure max link bw - the spec doesn't
> > +	 * seem to suggest we should do otherwise.
> > +	 */
> > +	limits->min_rate = limits->max_rate =
> > +		intel_dp_max_link_rate(intel_dp);
> > +
> > +	limits->min_lane_count = limits->max_lane_count =
> > +		intel_dp_max_lane_count(intel_dp);
> > +
> > +	limits->min_bpp = intel_dp_min_bpp(crtc_state->output_format);
> > +	/*
> > +	 * FIXME: If all the streams can't fit into the link with
> > +	 * their current pipe_bpp we should reduce pipe_bpp across
> > +	 * the board until things start to fit. Until then we
> > +	 * limit to <= 8bpc since that's what was hardcoded for all
> > +	 * MST streams previously. This hack should be removed once
> > +	 * we have the proper retry logic in place.
> > +	 */
> > +	limits->max_bpp = min(crtc_state->pipe_bpp, 24);
> > +
> > +	intel_dp_adjust_compliance_config(intel_dp, crtc_state, limits);
> > +}
> > +
> >  static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
> >  				       struct intel_crtc_state *pipe_config,
> >  				       struct drm_connector_state *conn_state)
> > @@ -329,28 +358,7 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
> >  		intel_dp_mst_has_audio(conn_state) &&
> >  		intel_audio_compute_config(encoder, pipe_config, conn_state);
> >  
> > -	/*
> > -	 * for MST we always configure max link bw - the spec doesn't
> > -	 * seem to suggest we should do otherwise.
> > -	 */
> > -	limits.min_rate =
> > -	limits.max_rate = intel_dp_max_link_rate(intel_dp);
> > -
> > -	limits.min_lane_count =
> > -	limits.max_lane_count = intel_dp_max_lane_count(intel_dp);
> > -
> > -	limits.min_bpp = intel_dp_min_bpp(pipe_config->output_format);
> > -	/*
> > -	 * FIXME: If all the streams can't fit into the link with
> > -	 * their current pipe_bpp we should reduce pipe_bpp across
> > -	 * the board until things start to fit. Until then we
> > -	 * limit to <= 8bpc since that's what was hardcoded for all
> > -	 * MST streams previously. This hack should be removed once
> > -	 * we have the proper retry logic in place.
> > -	 */
> > -	limits.max_bpp = min(pipe_config->pipe_bpp, 24);
> > -
> > -	intel_dp_adjust_compliance_config(intel_dp, pipe_config, &limits);
> > +	intel_dp_mst_compute_config_limits(intel_dp, pipe_config, &limits);
> >  
> >  	ret = intel_dp_mst_compute_link_config(encoder, pipe_config,
> >  					       conn_state, &limits);
> > -- 
> > 2.37.2
> 
> -- 
> Ville Syrjälä
> Intel


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